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Commit Graph

9334 Commits

Author SHA1 Message Date
Joonsoo Kim
d56e84b406 mm/cma_debug: correct size input to bitmap function
In CMA, 1 bit in bitmap means 1 << order_per_bits pages so size of
bitmap is cma->count >> order_per_bits rather than just cma->count.
This patch fixes it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Stefan Strogin <stefan.strogin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-17 16:39:54 -07:00
Joonsoo Kim
2292c0b1c4 mm/cma_debug: fix debugging alloc/free interface
CMA has alloc/free interface for debugging.  It is intended that
alloc/free occurs in specific CMA region, but, currently, alloc/free
interface is on root dir due to the bug so we can't select CMA region
where alloc/free happens.

This patch fixes this problem by making alloc/free interface per CMA
region.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Stefan Strogin <stefan.strogin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-17 16:39:54 -07:00
Joonsoo Kim
e2cfc91120 mm/page_owner: set correct gfp_mask on page_owner
Currently, we set wrong gfp_mask to page_owner info in case of isolated
freepage by compaction and split page.  It causes incorrect mixed
pageblock report that we can get from '/proc/pagetypeinfo'.  This metric
is really useful to measure fragmentation effect so should be accurate.
This patch fixes it by setting correct information.

Without this patch, after kernel build workload is finished, number of
mixed pageblock is 112 among roughly 210 movable pageblocks.

But, with this fix, output shows that mixed pageblock is just 57.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-17 16:39:54 -07:00
Joonsoo Kim
f3a14ced32 mm/page_owner: fix possible access violation
When I tested my new patches, I found that page pointer which is used
for setting page_owner information is changed.  This is because page
pointer is used to set new migratetype in loop.  After this work, page
pointer could be out of bound.  If this wrong pointer is used for
page_owner, access violation happens.  Below is error message that I
got.

  BUG: unable to handle kernel paging request at 0000000000b00018
  IP: [<ffffffff81025f30>] save_stack_address+0x30/0x40
  PGD 1af2d067 PUD 166e0067 PMD 0
  Oops: 0002 [#1] SMP
  ...snip...
  Call Trace:
    print_context_stack+0xcf/0x100
    dump_trace+0x15f/0x320
    save_stack_trace+0x2f/0x50
    __set_page_owner+0x46/0x70
    __isolate_free_page+0x1f7/0x210
    split_free_page+0x21/0xb0
    isolate_freepages_block+0x1e2/0x410
    compaction_alloc+0x22d/0x2d0
    migrate_pages+0x289/0x8b0
    compact_zone+0x409/0x880
    compact_zone_order+0x6d/0x90
    try_to_compact_pages+0x110/0x210
    __alloc_pages_direct_compact+0x3d/0xe6
    __alloc_pages_nodemask+0x6cd/0x9a0
    alloc_pages_current+0x91/0x100
    runtest_store+0x296/0xa50
    simple_attr_write+0xbd/0xe0
    __vfs_write+0x28/0xf0
    vfs_write+0xa9/0x1b0
    SyS_write+0x46/0xb0
    system_call_fastpath+0x16/0x75

This patch fixes this error by moving up set_page_owner().

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-17 16:39:54 -07:00
Mel Gorman
ae026b2aa1 mm, meminit: suppress unused memory variable warning
The kbuild test robot reported the following

  tree:   git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
  head:   14a6f1989d
  commit: 3b242c66cc x86: mm: enable deferred struct page initialisation on x86-64
  date:   3 days ago
  config: x86_64-randconfig-x006-201527 (attached as .config)
  reproduce:
    git checkout 3b242c66cc
    # save the attached .config to linux build tree
    make ARCH=x86_64

  All warnings (new ones prefixed by >>):

     mm/page_alloc.c: In function 'early_page_uninitialised':
  >> mm/page_alloc.c:247:6: warning: unused variable 'nid' [-Wunused-variable]
       int nid = early_pfn_to_nid(pfn);

It's due to the NODE_DATA macro ignoring the nid parameter on !NUMA
configurations.  This patch avoids the warning by not declaring nid.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-17 16:39:53 -07:00
Kirill A. Shutemov
6b7339f4c3 mm: avoid setting up anonymous pages into file mapping
Reading page fault handler code I've noticed that under right
circumstances kernel would map anonymous pages into file mappings: if
the VMA doesn't have vm_ops->fault() and the VMA wasn't fully populated
on ->mmap(), kernel would handle page fault to not populated pte with
do_anonymous_page().

Let's change page fault handler to use do_anonymous_page() only on
anonymous VMA (->vm_ops == NULL) and make sure that the VMA is not
shared.

For file mappings without vm_ops->fault() or shred VMA without vm_ops,
page fault on pte_none() entry would lead to SIGBUS.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Willy Tarreau <w@1wt.eu>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-09 11:12:48 -07:00
Linus Torvalds
1dc51b8288 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull more vfs updates from Al Viro:
 "Assorted VFS fixes and related cleanups (IMO the most interesting in
  that part are f_path-related things and Eric's descriptor-related
  stuff).  UFS regression fixes (it got broken last cycle).  9P fixes.
  fs-cache series, DAX patches, Jan's file_remove_suid() work"

[ I'd say this is much more than "fixes and related cleanups".  The
  file_table locking rule change by Eric Dumazet is a rather big and
  fundamental update even if the patch isn't huge.   - Linus ]

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits)
  9p: cope with bogus responses from server in p9_client_{read,write}
  p9_client_write(): avoid double p9_free_req()
  9p: forgetting to cancel request on interrupted zero-copy RPC
  dax: bdev_direct_access() may sleep
  block: Add support for DAX reads/writes to block devices
  dax: Use copy_from_iter_nocache
  dax: Add block size note to documentation
  fs/file.c: __fget() and dup2() atomicity rules
  fs/file.c: don't acquire files->file_lock in fd_install()
  fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation
  vfs: avoid creation of inode number 0 in get_next_ino
  namei: make set_root_rcu() return void
  make simple_positive() public
  ufs: use dir_pages instead of ufs_dir_pages()
  pagemap.h: move dir_pages() over there
  remove the pointless include of lglock.h
  fs: cleanup slight list_entry abuse
  xfs: Correctly lock inode when removing suid and file capabilities
  fs: Call security_ops->inode_killpriv on truncate
  fs: Provide function telling whether file_remove_privs() will do anything
  ...
2015-07-04 19:36:06 -07:00
Linus Torvalds
1e512b08da Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
 "Mainly sending this off now for the writeback fixes, since they fix a
  real regression introduced with the cgroup writeback changes.  The
  NVMe fix could wait for next pull for this series, but it's simple
  enough that we might as well include it.

  This contains:

   - two cgroup writeback fixes from Tejun, fixing a user reported issue
     with luks crypt devices hanging when being closed.

   - NVMe error cleanup fix from Jon Derrick, fixing a case where we'd
     attempt to free an unregistered IRQ"

* 'for-linus' of git://git.kernel.dk/linux-block:
  NVMe: Fix irq freeing when queue_request_irq fails
  writeback: don't drain bdi_writeback_congested on bdi destruction
  writeback: don't embed root bdi_writeback_congested in bdi_writeback
2015-07-03 12:12:16 -07:00
Linus Torvalds
9d90f03531 Replace module_init with appropriate alternate initcall in non modules.
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Merge tag 'module_init-alternate_initcall-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

Pull module_init replacement part two from Paul Gortmaker:
 "Replace module_init with appropriate alternate initcall in non
  modules.

  This series converts non-modular code that is using the module_init()
  call to hook itself into the system to instead use one of our
  alternate priority initcalls.

  Unlike the previous series that used device_initcall and hence was a
  runtime no-op, these commits change to one of the alternate initcalls,
  because (a) we have them and (b) it seems like the right thing to do.

  For example, it would seem logical to use arch_initcall for arch
  specific setup code and fs_initcall for filesystem setup code.

  This does mean however, that changes in the init ordering will be
  taking place, and so there is a small risk that some kind of implicit
  init ordering issue may lie uncovered.  But I think it is still better
  to give these ones sensible priorities than to just assign them all to
  device_initcall in order to exactly preserve the old ordering.

  Thad said, we have already made similar changes in core kernel code in
  commit c96d6660dc ("kernel: audit/fix non-modular users of
  module_init in core code") without any regressions reported, so this
  type of change isn't without precedent.  It has also got the same
  local testing and linux-next coverage as all the other pull requests
  that I'm sending for this merge window have got.

  Once again, there is an unused module_exit function removal that shows
  up as an outlier upon casual inspection of the diffstat"

* tag 'module_init-alternate_initcall-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
  x86: perf_event_intel_pt.c: use arch_initcall to hook in enabling
  x86: perf_event_intel_bts.c: use arch_initcall to hook in enabling
  mm/page_owner.c: use late_initcall to hook in enabling
  lib/list_sort: use late_initcall to hook in self tests
  arm: use subsys_initcall in non-modular pl320 IPC code
  powerpc: don't use module_init for non-modular core hugetlb code
  powerpc: use subsys_initcall for Freescale Local Bus
  x86: don't use module_init for non-modular core bootflag code
  netfilter: don't use module_init/exit in core IPV4 code
  fs/notify: don't use module_init for non-modular inotify_user code
  mm: replace module_init usages with subsys_initcall in nommu.c
2015-07-02 10:36:29 -07:00
Tejun Heo
a20135ffbc writeback: don't drain bdi_writeback_congested on bdi destruction
52ebea749a ("writeback: make backing_dev_info host cgroup-specific
bdi_writebacks") made bdi (backing_dev_info) host per-cgroup wb's
(bdi_writeback's).  As the congested state needs to be per-wb and
referenced from blkcg side and multiple wbs, the patch made all
non-root cong's (bdi_writeback_congested's) reference counted and
indexed on bdi.

When a bdi is destroyed, cgwb_bdi_destroy() tries to drain all
non-root cong's; however, this can hang indefinitely because wb's can
also be referenced from blkcg_gq's which are destroyed after bdi
destruction is complete.

This patch fixes the bug by updating bdi destruction to not wait for
cong's to drain.  A cong is unlinked from bdi->cgwb_congested_tree on
bdi destuction regardless of its reference count as the bdi may go
away any point after destruction.  wb_congested_put() checks whether
the cong is already unlinked on release.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Jon Christopherson <jon@jons.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=100681
Fixes: 52ebea749a ("writeback: make backing_dev_info host cgroup-specific bdi_writebacks")
Tested-by: Jon Christopherson <jon@jons.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-02 08:46:00 -06:00
Tejun Heo
a13f35e871 writeback: don't embed root bdi_writeback_congested in bdi_writeback
52ebea749a ("writeback: make backing_dev_info host cgroup-specific
bdi_writebacks") made bdi (backing_dev_info) host per-cgroup wb's
(bdi_writeback's).  As the congested state needs to be per-wb and
referenced from blkcg side and multiple wbs, the patch made all
non-root cong's (bdi_writeback_congested's) reference counted and
indexed on bdi.

When a bdi is destroyed, cgwb_bdi_destroy() tries to drain all
non-root cong's; however, this can hang indefinitely because wb's can
also be referenced from blkcg_gq's which are destroyed after bdi
destruction is complete.

To fix the bug, bdi destruction will be updated to not wait for cong's
to drain, which naturally means that cong's may outlive the associated
bdi.  This is fine for non-root cong's but is problematic for the root
cong's which are embedded in their bdi's as they may end up getting
dereferenced after the containing bdi's are freed.

This patch makes root cong's behave the same as non-root cong's.  They
are no longer embedded in their bdi's but allocated separately during
bdi initialization, indexed and reference counted the same way.

* As cong handling is the same for all wb's, wb->congested
  initialization is moved into wb_init().

* When !CONFIG_CGROUP_WRITEBACK, there was no indexing or refcnting.
  bdi->wb_congested is now a pointer pointing to the root cong
  allocated during bdi init and minimal refcnting operations are
  implemented.

* The above makes root wb init paths diverge depending on
  CONFIG_CGROUP_WRITEBACK.  root wb init is moved to cgwb_bdi_init().

This patch in itself shouldn't cause any consequential behavior
differences but prepares for the actual fix.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Jon Christopherson <jon@jons.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=100681
Tested-by: Jon Christopherson <jon@jons.org>

Added <linux/slab.h> include to backing-dev.h for kfree() definition.

Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-02 08:46:00 -06:00
Linus Torvalds
2d01eedf1d Merge branch 'akpm' (patches from Andrew)
Merge third patchbomb from Andrew Morton:

 - the rest of MM

 - scripts/gdb updates

 - ipc/ updates

 - lib/ updates

 - MAINTAINERS updates

 - various other misc things

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (67 commits)
  genalloc: rename of_get_named_gen_pool() to of_gen_pool_get()
  genalloc: rename dev_get_gen_pool() to gen_pool_get()
  x86: opt into HAVE_COPY_THREAD_TLS, for both 32-bit and 64-bit
  MAINTAINERS: add zpool
  MAINTAINERS: BCACHE: Kent Overstreet has changed email address
  MAINTAINERS: move Jens Osterkamp to CREDITS
  MAINTAINERS: remove unused nbd.h pattern
  MAINTAINERS: update brcm gpio filename pattern
  MAINTAINERS: update brcm dts pattern
  MAINTAINERS: update sound soc intel patterns
  MAINTAINERS: remove website for paride
  MAINTAINERS: update Emulex ocrdma email addresses
  bcache: use kvfree() in various places
  libcxgbi: use kvfree() in cxgbi_free_big_mem()
  target: use kvfree() in session alloc and free
  IB/ehca: use kvfree() in ipz_queue_{cd}tor()
  drm/nouveau/gem: use kvfree() in u_free()
  drm: use kvfree() in drm_free_large()
  cxgb4: use kvfree() in t4_free_mem()
  cxgb3: use kvfree() in cxgb_free_mem()
  ...
2015-07-01 17:47:51 -07:00
Christoph Lameter
ae6f2462e5 Add __init attribute to new_kmalloc_cache
Avoid the warning:

  WARNING: mm/built-in.o(.text.unlikely+0xc22): Section mismatch in reference from the function .new_kmalloc_cache() to the variable .init.rodata:kmalloc_info
  The function .new_kmalloc_cache() references
  the variable __initconst kmalloc_info.

Signed-off-by: Christoph Lameter <cl@linux.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-01 14:22:33 -07:00
Mel Gorman
0e1cc95b4c mm: meminit: finish initialisation of struct pages before basic setup
Waiman Long reported that 24TB machines hit OOM during basic setup when
struct page initialisation was deferred.  One approach is to initialise
memory on demand but it interferes with page allocator paths.  This patch
creates dedicated threads to initialise memory before basic setup.  It
then blocks on a rw_semaphore until completion as a wait_queue and counter
is overkill.  This may be slower to boot but it's simplier overall and
also gets rid of a section mangling which existed so kswapd could do the
initialisation.

[akpm@linux-foundation.org: include rwsem.h, use DECLARE_RWSEM, fix comment, remove unneeded cast]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Waiman Long <waiman.long@hp.com
Cc: Nathan Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Scott Norton <scott.norton@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:56 -07:00
Mel Gorman
74033a798f mm: meminit: remove mminit_verify_page_links
mminit_verify_page_links() is an extremely paranoid check that was
introduced when memory initialisation was being heavily reworked.
Profiles indicated that up to 10% of parallel memory initialisation was
spent on checking this for every page.  The cost could be reduced but in
practice this check only found problems very early during the
initialisation rewrite and has found nothing since.  This patch removes an
expensive unnecessary check.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:56 -07:00
Mel Gorman
ac5d2539b2 mm: meminit: reduce number of times pageblocks are set during struct page init
During parallel sturct page initialisation, ranges are checked for every
PFN unnecessarily which increases boot times.  This patch alters when the
ranges are checked.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:56 -07:00
Mel Gorman
a4de83dd33 mm: meminit: free pages in large chunks where possible
Parallel struct page frees pages one at a time. Try free pages as single
large pages where possible.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:56 -07:00
Mel Gorman
54608c3f3a mm: meminit: minimise number of pfn->page lookups during initialisation
Deferred struct page initialisation is using pfn_to_page() on every PFN
unnecessarily.  This patch minimises the number of lookups and scheduler
checks.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:56 -07:00
Mel Gorman
7e18adb4f8 mm: meminit: initialise remaining struct pages in parallel with kswapd
Only a subset of struct pages are initialised at the moment.  When this
patch is applied kswapd initialise the remaining struct pages in parallel.

This should boot faster by spreading the work to multiple CPUs and
initialising data that is local to the CPU.  The user-visible effect on
large machines is that free memory will appear to rapidly increase early
in the lifetime of the system until kswapd reports that all memory is
initialised in the kernel log.  Once initialised there should be no other
user-visibile effects.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:56 -07:00
Mel Gorman
3a80a7fa79 mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set
This patch initalises all low memory struct pages and 2G of the highest
zone on each node during memory initialisation if
CONFIG_DEFERRED_STRUCT_PAGE_INIT is set.  That config option cannot be set
but will be available in a later patch.  Parallel initialisation of struct
page depends on some features from memory hotplug and it is necessary to
alter alter section annotations.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:56 -07:00
Mel Gorman
75a592a471 mm: meminit: inline some helper functions
early_pfn_in_nid() and meminit_pfn_in_nid() are small functions that are
unnecessarily visible outside memory initialisation.  As well as
unnecessary visibility, it's unnecessary function call overhead when
initialising pages.  This patch moves the helpers inline.

[akpm@linux-foundation.org: fix build]
[mhocko@suse.cz: fix build]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:56 -07:00
Mel Gorman
8a942fdea5 mm: meminit: make __early_pfn_to_nid SMP-safe and introduce meminit_pfn_in_nid
__early_pfn_to_nid() use static variables to cache recent lookups as
memblock lookups are very expensive but it assumes that memory
initialisation is single-threaded.  Parallel initialisation of struct
pages will break that assumption so this patch makes __early_pfn_to_nid()
SMP-safe by requiring the caller to cache recent search information.
early_pfn_to_nid() keeps the same interface but is only safe to use early
in boot due to the use of a global static variable.  meminit_pfn_in_nid()
is an SMP-safe version that callers must maintain their own state for.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:56 -07:00
Mel Gorman
d70ddd7a5d mm: page_alloc: pass PFN to __free_pages_bootmem
__free_pages_bootmem prepares a page for release to the buddy allocator
and assumes that the struct page is initialised.  Parallel initialisation
of struct pages defers initialisation and __free_pages_bootmem can be
called for struct pages that cannot yet map struct page to PFN.  This
patch passes PFN to __free_pages_bootmem with no other functional change.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:55 -07:00
Nathan Zimmer
92923ca3aa mm: meminit: only set page reserved in the memblock region
Currently each page struct is set as reserved upon initialization.  This
patch leaves the reserved bit clear and only sets the reserved bit when it
is known the memory was allocated by the bootmem allocator.  This makes it
easier to distinguish between uninitialised struct pages and reserved
struct pages in later patches.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:55 -07:00
Robin Holt
1e8ce83cd1 mm: meminit: move page initialization into a separate function
Currently, memmap_init_zone() has all the smarts for initializing a single
page.  A subset of this is required for parallel page initialisation and
so this patch breaks up the monolithic function in preparation.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:55 -07:00
Robin Holt
8e7a7f8619 memblock: introduce a for_each_reserved_mem_region iterator
Struct page initialisation had been identified as one of the reasons why
large machines take a long time to boot. Patches were posted a long time ago
to defer initialisation until they were first used.  This was rejected on
the grounds it should not be necessary to hurt the fast paths. This series
reuses much of the work from that time but defers the initialisation of
memory to kswapd so that one thread per node initialises memory local to
that node.

After applying the series and setting the appropriate Kconfig variable I
see this in the boot log on a 64G machine

[    7.383764] kswapd 0 initialised deferred memory in 188ms
[    7.404253] kswapd 1 initialised deferred memory in 208ms
[    7.411044] kswapd 3 initialised deferred memory in 216ms
[    7.411551] kswapd 2 initialised deferred memory in 216ms

On a 1TB machine, I see

[    8.406511] kswapd 3 initialised deferred memory in 1116ms
[    8.428518] kswapd 1 initialised deferred memory in 1140ms
[    8.435977] kswapd 0 initialised deferred memory in 1148ms
[    8.437416] kswapd 2 initialised deferred memory in 1148ms

Once booted the machine appears to work as normal. Boot times were measured
from the time shutdown was called until ssh was available again.  In the
64G case, the boot time savings are negligible. On the 1TB machine, the
savings were 16 seconds.

Nate Zimmer said:

: On an older 8 TB box with lots and lots of cpus the boot time, as
: measure from grub to login prompt, the boot time improved from 1484
: seconds to exactly 1000 seconds.

Waiman Long said:

: I ran a bootup timing test on a 12-TB 16-socket IvyBridge-EX system.  From
: grub menu to ssh login, the bootup time was 453s before the patch and 265s
: after the patch - a saving of 188s (42%).

Daniel Blueman said:

: On a 7TB, 1728-core NumaConnect system with 108 NUMA nodes, we're seeing
: stock 4.0 boot in 7136s.  This drops to 2159s, or a 70% reduction with
: this patchset.  Non-temporal PMD init (https://lkml.org/lkml/2015/4/23/350)
: drops this to 1045s.

This patch (of 13):

As part of initializing struct page's in 2MiB chunks, we noticed that at
the end of free_all_bootmem(), there was nothing which had forced the
reserved/allocated 4KiB pages to be initialized.

This helper function will be used for that expansion.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nate Zimmer <nzimmer@sgi.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:55 -07:00
Christoph Lameter
a9730fca99 Fix kmalloc slab creation sequence
This patch restores the slab creation sequence that was broken by commit
4066c33d03 and also reverts the portions that introduced the
KMALLOC_LOOP_XXX macros. Those can never really work since the slab creation
is much more complex than just going from a minimum to a maximum number.

The latest upstream kernel boots cleanly on my machine with a 64 bit x86
configuration under KVM using either SLAB or SLUB.

Fixes: 4066c33d03 ("support the slub_debug boot option")
Reported-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-29 10:49:51 -07:00
Linus Torvalds
e382608254 This patch series contains several clean ups and even a new trace clock
"monitonic raw". Also some enhancements to make the ring buffer even
 faster. But the biggest and most noticeable change is the renaming of
 the ftrace* files, structures and variables that have to deal with
 trace events.
 
 Over the years I've had several developers tell me about their confusion
 with what ftrace is compared to events. Technically, "ftrace" is the
 infrastructure to do the function hooks, which include tracing and also
 helps with live kernel patching. But the trace events are a separate
 entity altogether, and the files that affect the trace events should
 not be named "ftrace". These include:
 
   include/trace/ftrace.h	->	include/trace/trace_events.h
   include/linux/ftrace_event.h	->	include/linux/trace_events.h
 
 Also, functions that are specific for trace events have also been renamed:
 
   ftrace_print_*()		->	trace_print_*()
   (un)register_ftrace_event()	->	(un)register_trace_event()
   ftrace_event_name()		->	trace_event_name()
   ftrace_trigger_soft_disabled()->	trace_trigger_soft_disabled()
   ftrace_define_fields_##call() ->	trace_define_fields_##call()
   ftrace_get_offsets_##call()	->	trace_get_offsets_##call()
 
 Structures have been renamed:
 
   ftrace_event_file		->	trace_event_file
   ftrace_event_{call,class}	->	trace_event_{call,class}
   ftrace_event_buffer		->	trace_event_buffer
   ftrace_subsystem_dir		->	trace_subsystem_dir
   ftrace_event_raw_##call	->	trace_event_raw_##call
   ftrace_event_data_offset_##call->	trace_event_data_offset_##call
   ftrace_event_type_funcs_##call ->	trace_event_type_funcs_##call
 
 And a few various variables and flags have also been updated.
 
 This has been sitting in linux-next for some time, and I have not heard
 a single complaint about this rename breaking anything. Mostly because
 these functions, variables and structures are mostly internal to the
 tracing system and are seldom (if ever) used by anything external to that.
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Merge tag 'trace-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "This patch series contains several clean ups and even a new trace
  clock "monitonic raw".  Also some enhancements to make the ring buffer
  even faster.  But the biggest and most noticeable change is the
  renaming of the ftrace* files, structures and variables that have to
  deal with trace events.

  Over the years I've had several developers tell me about their
  confusion with what ftrace is compared to events.  Technically,
  "ftrace" is the infrastructure to do the function hooks, which include
  tracing and also helps with live kernel patching.  But the trace
  events are a separate entity altogether, and the files that affect the
  trace events should not be named "ftrace".  These include:

    include/trace/ftrace.h         ->    include/trace/trace_events.h
    include/linux/ftrace_event.h   ->    include/linux/trace_events.h

  Also, functions that are specific for trace events have also been renamed:

    ftrace_print_*()               ->    trace_print_*()
    (un)register_ftrace_event()    ->    (un)register_trace_event()
    ftrace_event_name()            ->    trace_event_name()
    ftrace_trigger_soft_disabled() ->    trace_trigger_soft_disabled()
    ftrace_define_fields_##call()  ->    trace_define_fields_##call()
    ftrace_get_offsets_##call()    ->    trace_get_offsets_##call()

  Structures have been renamed:

    ftrace_event_file              ->    trace_event_file
    ftrace_event_{call,class}      ->    trace_event_{call,class}
    ftrace_event_buffer            ->    trace_event_buffer
    ftrace_subsystem_dir           ->    trace_subsystem_dir
    ftrace_event_raw_##call        ->    trace_event_raw_##call
    ftrace_event_data_offset_##call->    trace_event_data_offset_##call
    ftrace_event_type_funcs_##call ->    trace_event_type_funcs_##call

  And a few various variables and flags have also been updated.

  This has been sitting in linux-next for some time, and I have not
  heard a single complaint about this rename breaking anything.  Mostly
  because these functions, variables and structures are mostly internal
  to the tracing system and are seldom (if ever) used by anything
  external to that"

* tag 'trace-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
  ring_buffer: Allow to exit the ring buffer benchmark immediately
  ring-buffer-benchmark: Fix the wrong type
  ring-buffer-benchmark: Fix the wrong param in module_param
  ring-buffer: Add enum names for the context levels
  ring-buffer: Remove useless unused tracing_off_permanent()
  ring-buffer: Give NMIs a chance to lock the reader_lock
  ring-buffer: Add trace_recursive checks to ring_buffer_write()
  ring-buffer: Allways do the trace_recursive checks
  ring-buffer: Move recursive check to per_cpu descriptor
  ring-buffer: Add unlikelys to make fast path the default
  tracing: Rename ftrace_get_offsets_##call() to trace_event_get_offsets_##call()
  tracing: Rename ftrace_define_fields_##call() to trace_event_define_fields_##call()
  tracing: Rename ftrace_event_type_funcs_##call to trace_event_type_funcs_##call
  tracing: Rename ftrace_data_offset_##call to trace_event_data_offset_##call
  tracing: Rename ftrace_raw_##call event structures to trace_event_raw_##call
  tracing: Rename ftrace_trigger_soft_disabled() to trace_trigger_soft_disabled()
  tracing: Rename FTRACE_EVENT_FL_* flags to EVENT_FILE_FL_*
  tracing: Rename struct ftrace_subsystem_dir to trace_subsystem_dir
  tracing: Rename ftrace_event_name() to trace_event_name()
  tracing: Rename FTRACE_MAX_EVENT to TRACE_EVENT_TYPE_MAX
  ...
2015-06-26 14:02:43 -07:00
Linus Torvalds
47a469421d Merge branch 'akpm' (patches from Andrew)
Merge second patchbomb from Andrew Morton:

 - most of the rest of MM

 - lots of misc things

 - procfs updates

 - printk feature work

 - updates to get_maintainer, MAINTAINERS, checkpatch

 - lib/ updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (96 commits)
  exit,stats: /* obey this comment */
  coredump: add __printf attribute to cn_*printf functions
  coredump: use from_kuid/kgid when formatting corename
  fs/reiserfs: remove unneeded cast
  NILFS2: support NFSv2 export
  fs/befs/btree.c: remove unneeded initializations
  fs/minix: remove unneeded cast
  init/do_mounts.c: add create_dev() failure log
  kasan: remove duplicate definition of the macro KASAN_FREE_PAGE
  fs/efs: femove unneeded cast
  checkpatch: emit "NOTE: <types>" message only once after multiple files
  checkpatch: emit an error when there's a diff in a changelog
  checkpatch: validate MODULE_LICENSE content
  checkpatch: add multi-line handling for PREFER_ETHER_ADDR_COPY
  checkpatch: suggest using eth_zero_addr() and eth_broadcast_addr()
  checkpatch: fix processing of MEMSET issues
  checkpatch: suggest using ether_addr_equal*()
  checkpatch: avoid NOT_UNIFIED_DIFF errors on cover-letter.patch files
  checkpatch: remove local from codespell path
  checkpatch: add --showfile to allow input via pipe to show filenames
  ...
2015-06-26 09:52:05 -07:00
Wang Long
bffacb9132 kasan: remove duplicate definition of the macro KASAN_FREE_PAGE
Remove duplicate definition of the macro KASAN_FREE_PAGE in
mm/kasan/kasan.h

Signed-off-by: Wang Long <long.wanglong@huawei.com>
Acked-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:42 -07:00
Dan Streetman
479305fd71 zpool: remove zpool_evict()
Remove zpool_evict() helper function.  As zbud is currently the only
zpool implementation that supports eviction, add zpool and zpool_ops
references to struct zbud_pool and directly call zpool_ops->evict(zpool,
handle) on eviction.

Currently zpool provides the zpool_evict helper which locks the zpool
list lock and searches through all pools to find the specific one
matching the caller, and call the corresponding zpool_ops->evict
function.  However, this is unnecessary, as the zbud pool can simply
keep a reference to the zpool that created it, as well as the zpool_ops,
and directly call the zpool_ops->evict function, when it needs to evict
a page.  This avoids a spinlock and list search in zpool for each
eviction.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:37 -07:00
Dan Streetman
cf41f5f496 zpool: change pr_info to pr_debug
Change the pr_info() calls to pr_debug().  There's no need for the extra
verbosity in the log.  Also change the msg formats to be consistent.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ganesh Mahendran <opensource.ganesh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:37 -07:00
Dan Streetman
c00ed16a9e zswap: runtime enable/disable
Change the "enabled" parameter to be configurable at runtime.  Remove the
enabled check from init(), and move it to the frontswap store() function;
when enabled, pages will be stored, and when disabled, pages won't be
stored.

This is almost identical to Seth's patch from 2 years ago:
http://lkml.iu.edu/hypermail/linux/kernel/1307.2/04289.html

[akpm@linux-foundation.org: tweak documentation]
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Suggested-by: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:37 -07:00
Marcin Jabrzyk
13a18a1c04 zsmalloc: remove obsolete ZSMALLOC_DEBUG
The DEBUG define in zsmalloc is useless, there is no usage of it at all.

Signed-off-by: Marcin Jabrzyk <m.jabrzyk@samsung.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:35 -07:00
Dominik Dingel
8408427e6b mm/hugetlb: remove unused arch hook prepare/release_hugepage
With s390 dropping support for emulated hugepages, the last user of
arch_prepare_hugepage and arch_release_hugepage is gone.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:35 -07:00
Linus Torvalds
e4bc13adfd Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-block
Pull cgroup writeback support from Jens Axboe:
 "This is the big pull request for adding cgroup writeback support.

  This code has been in development for a long time, and it has been
  simmering in for-next for a good chunk of this cycle too.  This is one
  of those problems that has been talked about for at least half a
  decade, finally there's a solution and code to go with it.

  Also see last weeks writeup on LWN:

        http://lwn.net/Articles/648292/"

* 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits)
  writeback, blkio: add documentation for cgroup writeback support
  vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB
  writeback: do foreign inode detection iff cgroup writeback is enabled
  v9fs: fix error handling in v9fs_session_init()
  bdi: fix wrong error return value in cgwb_create()
  buffer: remove unusued 'ret' variable
  writeback: disassociate inodes from dying bdi_writebacks
  writeback: implement foreign cgroup inode bdi_writeback switching
  writeback: add lockdep annotation to inode_to_wb()
  writeback: use unlocked_inode_to_wb transaction in inode_congested()
  writeback: implement unlocked_inode_to_wb transaction and use it for stat updates
  writeback: implement [locked_]inode_to_wb_and_lock_list()
  writeback: implement foreign cgroup inode detection
  writeback: make writeback_control track the inode being written back
  writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()
  mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use
  writeback: implement memcg writeback domain based throttling
  writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes
  writeback: implement memcg wb_domain
  writeback: update wb_over_bg_thresh() to use wb_domain aware operations
  ...
2015-06-25 16:00:17 -07:00
Linus Torvalds
bfffa1cc9d Merge branch 'for-4.2/core' of git://git.kernel.dk/linux-block
Pull core block IO update from Jens Axboe:
 "Nothing really major in here, mostly a collection of smaller
  optimizations and cleanups, mixed with various fixes.  In more detail,
  this contains:

   - Addition of policy specific data to blkcg for block cgroups.  From
     Arianna Avanzini.

   - Various cleanups around command types from Christoph.

   - Cleanup of the suspend block I/O path from Christoph.

   - Plugging updates from Shaohua and Jeff Moyer, for blk-mq.

   - Eliminating atomic inc/dec of both remaining IO count and reference
     count in a bio.  From me.

   - Fixes for SG gap and chunk size support for data-less (discards)
     IO, so we can merge these better.  From me.

   - Small restructuring of blk-mq shared tag support, freeing drivers
     from iterating hardware queues.  From Keith Busch.

   - A few cfq-iosched tweaks, from Tahsin Erdogan and me.  Makes the
     IOPS mode the default for non-rotational storage"

* 'for-4.2/core' of git://git.kernel.dk/linux-block: (35 commits)
  cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL
  cfq-iosched: fix sysfs oops when attempting to read unconfigured weights
  cfq-iosched: move group scheduling functions under ifdef
  cfq-iosched: fix the setting of IOPS mode on SSDs
  blktrace: Add blktrace.c to BLOCK LAYER in MAINTAINERS file
  block, cgroup: implement policy-specific per-blkcg data
  block: Make CFQ default to IOPS mode on SSDs
  block: add blk_set_queue_dying() to blkdev.h
  blk-mq: Shared tag enhancements
  block: don't honor chunk sizes for data-less IO
  block: only honor SG gap prevention for merges that contain data
  block: fix returnvar.cocci warnings
  block, dm: don't copy bios for request clones
  block: remove management of bi_remaining when restoring original bi_end_io
  block: replace trylock with mutex_lock in blkdev_reread_part()
  block: export blkdev_reread_part() and __blkdev_reread_part()
  suspend: simplify block I/O handling
  block: collapse bio bit space
  block: remove unused BIO_RW_BLOCK and BIO_EOF flags
  block: remove BIO_EOPNOTSUPP
  ...
2015-06-25 14:29:53 -07:00
Linus Torvalds
aefbef10e3 Merge branch 'akpm' (patches from Andrew)
Merge first patchbomb from Andrew Morton:

 - a few misc things

 - ocfs2 udpates

 - kernel/watchdog.c feature work (took ages to get right)

 - most of MM.  A few tricky bits are held up and probably won't make 4.2.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (91 commits)
  mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
  mm, thp: respect MPOL_PREFERRED policy with non-local node
  tmpfs: truncate prealloc blocks past i_size
  mm/memory hotplug: print the last vmemmap region at the end of hot add memory
  mm/mmap.c: optimization of do_mmap_pgoff function
  mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
  mm: kmemleak: avoid deadlock on the kmemleak object insertion error path
  mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
  mm: kmemleak: fix delete_object_*() race when called on the same memory block
  mm: kmemleak: allow safe memory scanning during kmemleak disabling
  memcg: convert mem_cgroup->under_oom from atomic_t to int
  memcg: remove unused mem_cgroup->oom_wakeups
  frontswap: allow multiple backends
  x86, mirror: x86 enabling - find mirrored memory ranges
  mm/memblock: allocate boot time data structures from mirrored memory
  mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute
  mm: do not ignore mapping_gfp_mask in page cache allocation paths
  mm/cma.c: fix typos in comments
  mm/oom_kill.c: print points as unsigned int
  mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages
  ...
2015-06-24 20:47:21 -07:00
Larry Finger
8a8c35fadf mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
Beginning at commit d52d3997f8 ("ipv6: Create percpu rt6_info"), the
following INFO splat is logged:

  ===============================
  [ INFO: suspicious RCU usage. ]
  4.1.0-rc7-next-20150612 #1 Not tainted
  -------------------------------
  kernel/sched/core.c:7318 Illegal context switch in RCU-bh read-side critical section!
  other info that might help us debug this:
  rcu_scheduler_active = 1, debug_locks = 0
   3 locks held by systemd/1:
   #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff815f0c8f>] rtnetlink_rcv+0x1f/0x40
   #1:  (rcu_read_lock_bh){......}, at: [<ffffffff816a34e2>] ipv6_add_addr+0x62/0x540
   #2:  (addrconf_hash_lock){+...+.}, at: [<ffffffff816a3604>] ipv6_add_addr+0x184/0x540
  stack backtrace:
  CPU: 0 PID: 1 Comm: systemd Not tainted 4.1.0-rc7-next-20150612 #1
  Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.20   04/17/2014
  Call Trace:
    dump_stack+0x4c/0x6e
    lockdep_rcu_suspicious+0xe7/0x120
    ___might_sleep+0x1d5/0x1f0
    __might_sleep+0x4d/0x90
    kmem_cache_alloc+0x47/0x250
    create_object+0x39/0x2e0
    kmemleak_alloc_percpu+0x61/0xe0
    pcpu_alloc+0x370/0x630

Additional backtrace lines are truncated.  In addition, the above splat
is followed by several "BUG: sleeping function called from invalid
context at mm/slub.c:1268" outputs.  As suggested by Martin KaFai Lau,
these are the clue to the fix.  Routine kmemleak_alloc_percpu() always
uses GFP_KERNEL for its allocations, whereas it should follow the gfp
from its callers.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@vger.kernel.org>	[3.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:46 -07:00
Vlastimil Babka
0867a57c4f mm, thp: respect MPOL_PREFERRED policy with non-local node
Since commit 077fcf116c ("mm/thp: allocate transparent hugepages on
local node"), we handle THP allocations on page fault in a special way -
for non-interleave memory policies, the allocation is only attempted on
the node local to the current CPU, if the policy's nodemask allows the
node.

This is motivated by the assumption that THP benefits cannot offset the
cost of remote accesses, so it's better to fallback to base pages on the
local node (which might still be available, while huge pages are not due
to fragmentation) than to allocate huge pages on a remote node.

The nodemask check prevents us from violating e.g.  MPOL_BIND policies
where the local node is not among the allowed nodes.  However, the
current implementation can still give surprising results for the
MPOL_PREFERRED policy when the preferred node is different than the
current CPU's local node.

In such case we should honor the preferred node and not use the local
node, which is what this patch does.  If hugepage allocation on the
preferred node fails, we fall back to base pages and don't try other
nodes, with the same motivation as is done for the local node hugepage
allocations.  The patch also moves the MPOL_INTERLEAVE check around to
simplify the hugepage specific test.

The difference can be demonstrated using in-tree transhuge-stress test
on the following 2-node machine where half memory on one node was
occupied to show the difference.

> numactl --hardware
available: 2 nodes (0-1)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 24 25 26 27 28 29 30 31 32 33 34 35
node 0 size: 7878 MB
node 0 free: 3623 MB
node 1 cpus: 12 13 14 15 16 17 18 19 20 21 22 23 36 37 38 39 40 41 42 43 44 45 46 47
node 1 size: 8045 MB
node 1 free: 7818 MB
node distances:
node   0   1
  0:  10  21
  1:  21  10

Before the patch:
> numactl -p0 -C0 ./transhuge-stress
transhuge-stress: 2.197 s/loop, 0.276 ms/page,   7249.168 MiB/s 7962 succeed,    0 failed, 1786 different pages

> numactl -p0 -C12 ./transhuge-stress
transhuge-stress: 2.962 s/loop, 0.372 ms/page,   5376.172 MiB/s 7962 succeed,    0 failed, 3873 different pages

Number of successful THP allocations corresponds to free memory on node 0 in
the first case and node 1 in the second case, i.e. -p parameter is ignored and
cpu binding "wins".

After the patch:
> numactl -p0 -C0 ./transhuge-stress
transhuge-stress: 2.183 s/loop, 0.274 ms/page,   7295.516 MiB/s 7962 succeed,    0 failed, 1760 different pages

> numactl -p0 -C12 ./transhuge-stress
transhuge-stress: 2.878 s/loop, 0.361 ms/page,   5533.638 MiB/s 7962 succeed,    0 failed, 1750 different pages

> numactl -p1 -C0 ./transhuge-stress
transhuge-stress: 4.628 s/loop, 0.581 ms/page,   3440.893 MiB/s 7962 succeed,    0 failed, 3918 different pages

The -p parameter is respected regardless of cpu binding.

> numactl -C0 ./transhuge-stress
transhuge-stress: 2.202 s/loop, 0.277 ms/page,   7230.003 MiB/s 7962 succeed,    0 failed, 1750 different pages

> numactl -C12 ./transhuge-stress
transhuge-stress: 3.020 s/loop, 0.379 ms/page,   5273.324 MiB/s 7962 succeed,    0 failed, 3916 different pages

Without -p parameter, hugepage restriction to CPU-local node works as before.

Fixes: 077fcf116c ("mm/thp: allocate transparent hugepages on local node")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:46 -07:00
Josef Bacik
afa2db2fb6 tmpfs: truncate prealloc blocks past i_size
One of the rocksdb people noticed that when you do something like this

    fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, 10M)
    pwrite(fd, buf, 5M, 0)
    ftruncate(5M)

on tmpfs, the file would still take up 10M: which led to super fun
issues because we were getting ENOSPC before we thought we should be
getting ENOSPC.  This patch fixes the problem, and mirrors what all the
other fs'es do (and was agreed to be the correct behaviour at LSF).

I tested it locally to make sure it worked properly with the following

    xfs_io -f -c "falloc -k 0 10M" -c "pwrite 0 5M" -c "truncate 5M" file

Without the patch we have "Blocks: 20480", with the patch we have the
correct value of "Blocks: 10240".

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Zhu Guihua
c435a39057 mm/memory hotplug: print the last vmemmap region at the end of hot add memory
When hot add two nodes continuously, we found the vmemmap region info is
a bit messed.  The last region of node 2 is printed when node 3 hot
added, like the following:

  Initmem setup node 2 [mem 0x0000000000000000-0xffffffffffffffff]
   On node 2 totalpages: 0
   Built 2 zonelists in Node order, mobility grouping on.  Total pages: 16090539
   Policy zone: Normal
   init_memory_mapping: [mem 0x40000000000-0x407ffffffff]
    [mem 0x40000000000-0x407ffffffff] page 1G
    [ffffea1000000000-ffffea10001fffff] PMD -> [ffff8a077d800000-ffff8a077d9fffff] on node 2
    [ffffea1000200000-ffffea10003fffff] PMD -> [ffff8a077de00000-ffff8a077dffffff] on node 2
  ...
    [ffffea101f600000-ffffea101f9fffff] PMD -> [ffff8a074ac00000-ffff8a074affffff] on node 2
    [ffffea101fa00000-ffffea101fdfffff] PMD -> [ffff8a074a800000-ffff8a074abfffff] on node 2
  Initmem setup node 3 [mem 0x0000000000000000-0xffffffffffffffff]
   On node 3 totalpages: 0
   Built 3 zonelists in Node order, mobility grouping on.  Total pages: 16090539
   Policy zone: Normal
   init_memory_mapping: [mem 0x60000000000-0x607ffffffff]
    [mem 0x60000000000-0x607ffffffff] page 1G
    [ffffea101fe00000-ffffea101fffffff] PMD -> [ffff8a074a400000-ffff8a074a5fffff] on node 2 <=== node 2 ???
    [ffffea1800000000-ffffea18001fffff] PMD -> [ffff8a074a600000-ffff8a074a7fffff] on node 3
    [ffffea1800200000-ffffea18005fffff] PMD -> [ffff8a074a000000-ffff8a074a3fffff] on node 3
    [ffffea1800600000-ffffea18009fffff] PMD -> [ffff8a0749c00000-ffff8a0749ffffff] on node 3
  ...

The cause is the last region was missed at the and of hot add memory,
and p_start, p_end, node_start were not reset, so when hot add memory to
a new node, it will consider they are not contiguous blocks and print
the previous one.  So we print the last vmemmap region at the end of hot
add memory to avoid the confusion.

Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Piotr Kwapulinski
e37609bb36 mm/mmap.c: optimization of do_mmap_pgoff function
The simple check for zero length memory mapping may be performed
earlier.  So that in case of zero length memory mapping some unnecessary
code is not executed at all.  It does not make the code less readable
and saves some CPU cycles.

Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
93ada579b0 mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
The kmemleak memory scanning uses finer grained object->lock spinlocks
primarily to avoid races with the memory block freeing.  However, the
pointer lookup in the rb tree requires the kmemleak_lock to be held.
This is currently done in the find_and_get_object() function for each
pointer-like location read during scanning.  While this allows a low
latency on kmemleak_*() callbacks on other CPUs, the memory scanning is
slower.

This patch moves the kmemleak_lock outside the scan_block() loop,
acquiring/releasing it only once per scanned memory block.  The
allow_resched logic is moved outside scan_block() and a new
scan_large_block() function is implemented which splits large blocks in
MAX_SCAN_SIZE chunks with cond_resched() calls in-between.  A redundant
(object->flags & OBJECT_NO_SCAN) check is also removed from
scan_object().

With this patch, the kmemleak scanning performance is significantly
improved: at least 50% with lock debugging disabled and over an order of
magnitude with lock proving enabled (on an arm64 system).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
9d5a4c730d mm: kmemleak: avoid deadlock on the kmemleak object insertion error path
While very unlikely (usually kmemleak or sl*b bug), the create_object()
function in mm/kmemleak.c may fail to insert a newly allocated object into
the rb tree.  When this happens, kmemleak disables itself and prints
additional information about the object already found in the rb tree.
Such printing is done with the parent->lock acquired, however the
kmemleak_lock is already held.  This is a potential race with the scanning
thread which acquires object->lock and kmemleak_lock in a

This patch removes the locking around the 'parent' object information
printing.  Such object cannot be freed or removed from object_tree_root
and object_list since kmemleak_lock is already held.  There is a very
small risk that some of the object data is being modified on another CPU
but the only downside is inconsistent information printing.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
5f369f374b mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
The kmemleak_do_cleanup() work thread already waits for the kmemleak_scan
thread to finish via kthread_stop().  Waiting in kthread_stop() while
scan_mutex is held may lead to deadlock if kmemleak_scan_thread() also
waits to acquire for scan_mutex.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
e781a9ab48 mm: kmemleak: fix delete_object_*() race when called on the same memory block
Calling delete_object_*() on the same pointer is not a standard use case
(unless there is a bug in the code calling kmemleak_free()).  However,
during kmemleak disabling (error or user triggered via /sys), there is a
potential race between kmemleak_free() calls on a CPU and
__kmemleak_do_cleanup() on a different CPU.

The current delete_object_*() implementation first performs a look-up
holding kmemleak_lock, increments the object->use_count and then
re-acquires kmemleak_lock to remove the object from object_tree_root and
object_list.

This patch simplifies the delete_object_*() mechanism to both look up
and remove an object from the object_tree_root and object_list
atomically (guarded by kmemleak_lock).  This allows safe concurrent
calls to delete_object_*() on the same pointer without additional
locking for synchronising the kmemleak_free_enabled flag.

A side effect is a slight improvement in the delete_object_*() performance
by avoiding acquiring kmemleak_lock twice and incrementing/decrementing
object->use_count.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
c5f3b1a51a mm: kmemleak: allow safe memory scanning during kmemleak disabling
The kmemleak scanning thread can run for minutes.  Callbacks like
kmemleak_free() are allowed during this time, the race being taken care
of by the object->lock spinlock.  Such lock also prevents a memory block
from being freed or unmapped while it is being scanned by blocking the
kmemleak_free() -> ...  -> __delete_object() function until the lock is
released in scan_object().

When a kmemleak error occurs (e.g.  it fails to allocate its metadata),
kmemleak_enabled is set and __delete_object() is no longer called on
freed objects.  If kmemleak_scan is running at the same time,
kmemleak_free() no longer waits for the object scanning to complete,
allowing the corresponding memory block to be freed or unmapped (in the
case of vfree()).  This leads to kmemleak_scan potentially triggering a
page fault.

This patch separates the kmemleak_free() enabling/disabling from the
overall kmemleak_enabled nob so that we can defer the disabling of the
object freeing tracking until the scanning thread completed.  The
kmemleak_free_part() is deliberately ignored by this patch since this is
only called during boot before the scanning thread started.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org>
Tested-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Tejun Heo
c2b42d3cad memcg: convert mem_cgroup->under_oom from atomic_t to int
memcg->under_oom tracks whether the memcg is under OOM conditions and is
an atomic_t counter managed with mem_cgroup_[un]mark_under_oom().  While
atomic_t appears to be simple synchronization-wise, when used as a
synchronization construct like here, it's trickier and more error-prone
due to weak memory ordering rules, especially around atomic_read(), and
false sense of security.

For example, both non-trivial read sites of memcg->under_oom are a bit
problematic although not being actually broken.

* mem_cgroup_oom_register_event()

  It isn't explicit what guarantees the memory ordering between event
  addition and memcg->under_oom check.  This isn't broken only because
  memcg_oom_lock is used for both event list and memcg->oom_lock.

* memcg_oom_recover()

  The lockless test doesn't have any explanation why this would be
  safe.

mem_cgroup_[un]mark_under_oom() are very cold paths and there's no point
in avoiding locking memcg_oom_lock there.  This patch converts
memcg->under_oom from atomic_t to int, puts their modifications under
memcg_oom_lock and documents why the lockless test in
memcg_oom_recover() is safe.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Tejun Heo
f4b90b70b7 memcg: remove unused mem_cgroup->oom_wakeups
Since commit 4942642080 ("mm: memcg: handle non-error OOM situations
more gracefully"), nobody uses mem_cgroup->oom_wakeups.  Remove it.

While at it, also fold memcg_wakeup_oom() into memcg_oom_recover() which
is its only user.  This cleanup was suggested by Michal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00